Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release.
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Prerequisites for Ethernet Management Ports
When connecting a PC to the Ethernet management port, you must first assign an IP address.
Information about the Ethernet Management Port
The Ethernet management port, also referred to as the Gi0/0 or GigabitEthernet0/0 port, is a VRF (VPN routing/forwarding) interface to which you can connect a PC. You can use the Ethernet management port instead of the switch console port for network management. When managing a switch stack, connect the PC to the Ethernet management port on a stack member.
Ethernet Management Port Direct Connection to a Switch
Figure 1. Connecting a Switch to a PC.
This figure displays how to connect the Ethernet management port to the PC for a switch or a standalone switch.
Ethernet Management Port Connection to Stack Switches using a Hub
In a stack with only stack switches, all the Ethernet management ports on the stack members are connected to a hub to which the PC is connected. The active link is from the Ethernet management port on the active switchthrough the hub, to the PC. If the active switch fails and a new active switch is elected, the active link is now from the Ethernet management port on the new active switch to the PC.
Figure 2. Connecting a Switch Stack to a PC.
This figure displays how a PC uses a hub to connect to a switch stack.
Ethernet Management Port and Routing
By default, the Ethernet management port is enabled. The switch cannot route packets from the Ethernet management port to a network port, and the reverse. Even though the Ethernet management port does not support routing, you may need to enable routing protocols on the port.
Figure 3. Network Example with Routing Protocols Enabled.
In the following figure, you must enable routing protocols on the Ethernet management port when the PC is multiple hops away from the switch and the packets must pass through multiple Layer 3 devices to reach the PC.
In the above figure , if the Ethernet management port and the network ports are associated with the same routing process, the routes are propagated as follows:
The routes from the Ethernet management port are propagated through the network ports to the network.
The routes from the network ports are propagated through the Ethernet management port to the network.
Because routing is not supported between the Ethernet management port and the network ports, traffic between these ports cannot be sent or received. If this happens, data packet loops occur between the ports, which disrupt the switch and network operation. To prevent the loops, configure route filters to avoid routes between the Ethernet management port and the network ports.
Supported Features on the Ethernet Management Port
The Ethernet management port supports these features:
Express Setup (only in switch stacks)
Telnet with passwords
Secure Shell (SSH)
SMNP (only the ENTITY-MIB and the IF-MIB)
Speed—10 Mb/s, 100 Mb/s, 1000 Mb/s, and autonegotiation
Duplex mode—Full, half, and autonegotiation
Cisco Discovery Protocol (CDP)
DHCP relay agent
IPv4 and IPv6 access control lists (ACLs)
Before enabling a feature on the Ethernet management port, make sure that the feature is supported. If you try to configure an unsupported feature on the Ethernet Management port, the feature might not work properly, and the switch might fail.
How to Configure the Ethernet Management Port
Disabling and Enabling the Ethernet Management Port
To disable or enable the Ethernet management port in the CLI, follow this procedure.
6.show interfaces gigabitethernet0/0
Command or Action
Switch# configure terminal
Enters global configuration mode.
Switch(config)# interface gigabitethernet0/0
Specifies the Ethernet management port in the CLI.
Disables the Ethernet management port.
Switch(config-if)# no shutdown
Enables the Ethernet management port.
Exits interface configuration mode.
show interfaces gigabitethernet0/0
Switch# show interfaces gigabitethernet0/0
Displays the link status.
To find out the link status to the PC, you can monitor the LED for the Ethernet management port. The LED is green (on) when the link is active, and the LED is off when the link is down. The LED is amber when there is a POST failure.
What to Do Next
Proceed to manage or configure your switch using the Ethernet management port. Refer to the Network Management Configuration Guide (Catalyst 3850 Switches).
System Management Configuration Guide (Catalyst 3850 Switches)
System Management Command Reference (Catalyst 3850 Switches)
Error Message Decoder
To help you research and resolve system error messages in this release, use the Error Message Decoder tool.
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